Thought I would share how we met the 90Db sound limit at Laguna Seca last year. Took the car over to Kwik Way Muffler in San Jose CA. They have been in business close to 50 years and love helping racers. They fabricated this little muffler to slide onto and clamp to the end of the SE 30 pipe. At the track sound was measured at 86.4 Db. It does rob about 7 HP according to dyno testing we recently did at TFB Sonoma. Anyway, if you would like something like this contact Bob at Kwik Way 408.244.4540

No issue with it touching the track surface. Note that the tailpipe is pointing up and to the left. This very likely helped in meeting the required 90Db limit. As the car passes the sound check booth this is pointed away from it.